Driving related measurements are a total clusterfuck. By default all distances are in miles. But distance markers along the motorways are placed at metric distances. But some markers are in yards. But then some are in fucking kilometres. And then you drive on the left, but of course there's a fucking road in London where you drive on the right. Because fuck you, that's why!

By the way, the highway code is available online for free, check it out - https://www.gov.uk/browse/driving/highway-code-road-safety